A number of different video encoding standards have been established for encoding digital video sequences. The Moving Picture Experts Group (MPEG), for example, has developed a number of standards including MPEG-1, MPEG-2 and MPEG-4. Other examples include the International Telecommunication Union (ITU) H.263 standard, and the emerging ITU H.264 standard. These video encoding standards generally support improved transmission efficiency of video sequences by encoding data in a compressed manner.
Video telephony (VT) permits users to share video and audio information to support applications such as videoconferencing. Exemplary video telephony standards include those defined by the Session Initiated Protocol (SIP), the ITU H.323 standard, and the ITU H.324 standard. In two-way VT, users send and receive video information. Some VT systems provide a picture-in-picture (PIP) feature that permits a user to view both incoming video from a remote user and outgoing video sent to a remote user.
With the PIP feature, outgoing video may be presented in a smaller picture overlaid on a larger picture containing the incoming video. The larger picture typically occupies an entire video frame. The smaller picture may occupy approximately twenty to twenty-five percent of the video frame, covering a portion of the larger picture. The PIP feature may permit the user to view outgoing video to ensure proper camera alignment. For example, a user may wish to ensure that his face, or another object, will be fully visible within the outgoing video frame. Using the PIP feature, the user can better position the camera to improve the content of the outgoing video.